It is unclear how angiogenesis and restoration of perfusion determine graft function after free parathyroid autotransplantation.We provide a new animal model allowing simultaneous and repetitive in vivo assessment of angiogenesis and endocrine function of parathyroid transplants. Methods:Fresh human parathyroid tissue from patients with secondary hyperparathyroidism was grafted into dorsal skinfold chamber preparations of athymic nude mi(CD1-nu BR; n=8). Equivalent pieces of the same human donor specimens were heat-inactivated and served as control grafts (n=7).Results:In all animals receiving parathyroid transplants human parathyroid hormone levels were detectable by species-specific ELISA analysis of plasma samples on day 5 after transplantationand increased by 2.5 fold over the observation (19 days) in contrst to controls (day 19: 82.5+/-29.3 vs. 0.0+/-0.0 pg/ml; p<0.05).Plasma Calcium-levels revealed no differences between the groups. On day 5 after transplantation intravital fluorescence microscopy revealed first murine angiogenic microvessels sprouting alongg non-perfused human donor vessels and one week later functional microvasculature was established in all parathyroid transplants. Histological analysis of HE- and vWF- contrast, control grafts were either necrotic and partly resorbed exhibiting no angiogenic activity or revealed well vascularized fat cells indicating fatty degeneration. Aditionally, species-specific Western blot analysis revealed vascular endothelial growth factor expression of parathyroid transplants as functional parameter of angiogenesis determining transplant function in vivo. Conclusion: This model may serve to understand mechanisms associated with specific parathyroid transplant angiogenesis and its significance for transplant function in order to optimize clinical success of autotransplantation in therapy-resistant patients.

Abstract

It is unclear how angiogenesis and restoration of perfusion determine graft function after free parathyroid autotransplantation.We provide a new animal model allowing simultaneous and repetitive in vivo assessment of angiogenesis and endocrine function of parathyroid transplants. Methods:Fresh human parathyroid tissue from patients with secondary hyperparathyroidism was grafted into dorsal skinfold chamber preparations of athymic nude mi(CD1-nu BR; n=8). Equivalent pieces of the same human donor specimens were heat-inactivated and served as control grafts (n=7).Results:In all animals receiving parathyroid transplants human parathyroid hormone levels were detectable by species-specific ELISA analysis of plasma samples on day 5 after transplantationand increased by 2.5 fold over the observation (19 days) in contrst to controls (day 19: 82.5+/-29.3 vs. 0.0+/-0.0 pg/ml; p<0.05).Plasma Calcium-levels revealed no differences between the groups. On day 5 after transplantation intravital fluorescence microscopy revealed first murine angiogenic microvessels sprouting alongg non-perfused human donor vessels and one week later functional microvasculature was established in all parathyroid transplants. Histological analysis of HE- and vWF- contrast, control grafts were either necrotic and partly resorbed exhibiting no angiogenic activity or revealed well vascularized fat cells indicating fatty degeneration. Aditionally, species-specific Western blot analysis revealed vascular endothelial growth factor expression of parathyroid transplants as functional parameter of angiogenesis determining transplant function in vivo. Conclusion: This model may serve to understand mechanisms associated with specific parathyroid transplant angiogenesis and its significance for transplant function in order to optimize clinical success of autotransplantation in therapy-resistant patients.